Transmission



May 12, 1942. Rom v 2,282,591

TRANSMISSION Filed Feb. 14 19.38 s Sheets- Shalet 1 P. ORR

TRANSMISS ION May 12, 1942.

Fiied Feb. 14, 1938 v 6 Shets-Sheet 2 P. RR

TRANSMISSION May 12, 1942.

Filed Feb. 14, 1938 ,,,,,,,f/ /1 IL,

6 Sheets-Sheet 4 May12,l9 42. RORR I TRANSMISSION Filed Fb. 14, 1958 s Sheets-Sheet s May' 1 942. O I y 2,282,591

' TRANSMISSION Filed Feb. 14. 1958 sheets-she d. s

governor, are used to drive the Patented May 12, 1942 UNITED 's'rAr -zs PATENT OFFICE zsazsai- I TBANSMISSIQN Palmer n,

l'dnncia'm, designer to Borg-War net @orporation, Chicago, 11]., a corporation of Illinois Application ream l4, 193's, Serial Nun-190,368

(or v e-cs4 9 ie. is...

since it is in the nature of an improvement thereof, but it is understood that the invention is not-limited in its application to the particular device described.

There has been devised an automatic speed ratio changing device or transmission which.

provides three forward speeds and a reverse by means'of gear trains adapted selectively to be connected to an engine through individual clutches or combinations of clutches, with oneway clutches in all but the highest ratio gear trains. .A-main speed responsive clutch is used through which all speeds are obtained, and additional. fluid operated clutches controlled by a gear'trains of lesser speed reduction ratio. I

It is desirable in automotive transmissions to provide a means for positively locking the wheels of the vehicle to the engine at gear ratios less than unity to render the compression in the engine available for braking purposes. In the transmission mentioned above, such a means has not been provided.

An object of this invention is a locking device for an automotive transmission which-is adapted to look a normally free-wheeling gear train to the engine to provide a two-way drive therebetween.

Another object is the provision of means, whereby a free-wheeling gear train may be locked for two-way drive while the engine is rotating and with a minimum of noise.

Still another object is to provide a locking device for a fluid-operated transmission having a single source of fiuid' under pressure, said device being likewise adapted to be fluid-operated and in no way interfering with the normal operation of the transmission.

These and other objects of the invention will become apparent from the following detailed description when taken together with the accompanying drawings which form a part thereof, and inwhioh a Fig. 1A is aside elevation in section of a portion of a fluid operated 1m:

Fig. 1B is aside elevation in section of the remaining portion of the fluid operated trans-- 53 mission oi Fig. 1A, said Figs. 1A and 13 being drawn to be placed side by side and read to eilhei'i his. 2 is a section taken through certain of the valves of Fig, 1B and showing the control for one oi said valves; 1

Fig. 3 is a section taken through the trans mission near the governor valve of Fig. 1B show ms the control for another of the valves:

Fig. 4 shows the means by which the governor controls still another of the valves;

Fig. 5 is an elevation of the novel locking means;

Figs. 6 and '3' are and elevations in section of.

v different parts of the locking'means of Fig. 5;

Fig.8 is a side elevation in section of the locking means: and I 9 to it inclusive are developed sections through the valves showing the paths of the fluid for various settings 'of the valves.

In its preferred form this invention comprises a fluid-operated jaw clutch which is adapted to lock the driven shaft of the transmission and one of the speed reduction ratio trains together around the free-wheeling or one-way clutch in said train. The movable element of the jaw clutch is in the form of a piston, and the fluid i'or operating the piston is controlled by a manually operated valve. The porting of the valve is so designed that the presence of the valve in the fluid system does not disturb the normal operation of-the remaining valves in the system. f To prevent clash when the teeth of the jaw clutch are engaged a balk'ring is used, and they 7 mission are shown.

\ The transmission is adapted to be inserted between a'drive shaft 20 and a driven shaft 20, a. portion of the latter shaft being included in the transmission and forming a part thereof. It is comprised of two main sections 22 and 23, section 22 being the main clutch section, and

section 23 constituting the speed reducing sec tion.

Main clutch section wheel 28 whichis bolted to aflange 25 on drive- 22 is comprised of afly shaft 26 and a clutclrcover 26. Within the space formed by fly wheel 24 and clutch cover 26 is a bi-partite' drum 21 formed by telescoping and welding together flanged discs 28 and 29.

Drum 21 and clutch cover 26 are adapted to be engaged frictionally to constitute a clutch 36.

movement of weights 36 will cause pressure plate 3| to move to the left (Fig. 1A) thereby compressing drum 21 between the pressure plate and. fly wheel 24. Suitable friction facings 33 and 34 may be used on drum 21 to prevent undue slipping. I

Drum 21 is rigidly connected to a flanged sleeve 36 whichis splined to a second sleeve 31 one portion 38 of which is toothed to form the first gear of the flrst gear reduction or lowest speed train.

Within drum 2'! are two multiple disc clutches 39 and 80, each of which has a set of plates 4| and 42 respectively mounted to rotate with a web 43.. Said web 43 is connected through vibration dampening springs 51 to a sleeve 58 which is splined to a long shaft 59 extending through both sections of the transmission. Plates 44 of disc 52, the latter being rigidly secured to disc 28 of drum 21.

Clutches 39 and 46 are selectively operated by fluid pressure acting upon diaphragms 53 and 54, which tend to urge plates 55 and 56 outward from web 43 to compress the plates of the clutches and thereby to operate said clutches.

It is,apparent thus far that main clutch 3| rotates gear 36 of the low speed train, clutch 39 rotates second speed gear 49 and clutch 46 roto form the mating member of said jaw clutch.

Suitable means (not shown) may be used to shift gear 65 to any one of three positions, the first of which causes the gear to mesh with gear 63 on the countershaft and to lock shafts 59 and 2| =through splines 66, 61 and 68, the second causes gear 65 to be out of mesh with gears 63 and the idler connected to gear 64 to provide a neutral position, and the third causes gear 65 to mesh with the reverse idler and also connects said gear 65 to shaft 2| directly through jaw clutch elements 16 and 1| for a positive reverse drive.

The various power transmitting trains provided by the transmission thus far described can be traced. Assuming that gear 65 is in position to mesh with gear 63, that is, in forward driving position, and that shaft 26 and its associated fly wheel 24 and clutch cover 26 are rotated sufliciently rapidly to cause clutch 36 to be engaged, the low speed train comprises clutch cover 26,

, drum 21, splined sleeves 36 and 31, gear 38, couneffective.

tates shaft 59. The various gear trains which cause driven shaft 2| to rotate at three different speeds relative to drive shaft 26 will now be described.

Referring particularly to Fig. 13, speed reduction section 23 is comprised of a plurality of gears mounted on long shaft 59 and adapted to cooperate with gears mounted on a countershaft 6|). Said countershaft gears are comprised of a gear 6| which is constantly in mesh with gear 38, a gear 62 constantly in mesh with gear 49, and gears 63 and 64, selectively meshable with a gear 65 concentric with shaft 59, gear 64 being indirectly meshable with gear 65 through an idler gear (not shown) to provide a reverse drive. Gears 62, 63 and 64 may /be members of a gear cluster so as to rotate together, and gear 6| may be'secured to gear 62 for rotation therewith.

Shaft 59 is piloted in shaft 2| and both shafts 1 are provided with external splines 66 and 61 respectively which are adapted to cooperate with an internally splined collar 68 for locking said shafts together. Gear 65 is mounted on collar 68 and is driven therefrom through a one-way clutch 69. Shaft 2| is also provided with a toothed flange 16 forming one element of a jaw clutch. a g r 5 is toothed intern ly at tershaft gears 6|, and 63, gear 65, one-way clutch 69, collar 68 and shaft 2|. For second speed it is necessary that clutch 39 shall be operated in addition to speed responsive clutch 30, and assuming that these conditions obtain, the power for second speed is transmitted from fly wheel 24 through clutch 38, splined sleeves 36 and 31, gear 38, countershaft gears and 62, gear 49, collar 41, one-way'clutch 46, annulus 45, clutch 39, web 43, vibration dampener 51, sleeve 58, shaft 59, and jaw clutch elements 66, 61 and 68 to shaft 2|. Gear 65 will overrun collar 68 through clutch 69 when second speed is made For high speed, i. e., direct 'drive, it is necessary that clutch 46 be made operative. The high speed train is then traceable from fly wheel 24'through clutch 36 as before, drum 21, annulus 52, clutch 46, web 43, vibration dampener 51, sleeve. 58, shaft 59, and jaw clutch elements 66, 61, 68 to shaft 2 Since web 43 will rotate faster than collar 41 of the second speed drive, clutch 46 will overrun as well as clutch 69 in high speed. To establish reverse, gear 65 is moved to the right (Fig. 1B) until-jaw clutch elements 16 and 1| are engaged and gear 65 is connected to gear 64 through the reverse idler. The power is then transmitted throughthe same elements as for low speed up to and including gear 64 and then through the idler, the gear 65, jaw clutch elements 16 and 1| to shaft 2|.

Thusfor the successful operation of the transmission device, it is necessary to operate three clutches, the first of which is mechanical and speed-responsive, and the remaining two of which are fluid operated. The fluid system for operating the clutches will now be described.

The fluid used may be any of the available oils such as are commonly used to lubricate transmissions, and is supplied from a reservoir 12'at the bottom of section 23. A pump (not 'shown) 'draws the oil from reservoir 12 when generally by reference character 19; and valve is locked up in second, is controlled'by 11, which is the valve by which the transmission a second manual control 86 (Fig. 2).

v The three valves 15, 16, and 11 are $0 inteb connected through portlngs that governor valve 16 normally controls the flow of fluid from the reservoir 12, but control may be taken from governor valve 16 by manually controlled valvev l5, and the transmission may be locked in second through valve 11. Theportings will be described in detail hereinafter. 7

Valve block 14 is provided with three grooves by the return movement of the eccentric disc in response to deceleration of the vehicle.

The manual control 18 for valve 15 is shown in Fig. 3, and comprises a Bowden wire I 88 secured to a button H19 in a housing H8. Said housing H9 is movable in the direction of motion of button I 99 within a second housing III, which is 8|, 82 and 83 which communicate with valves 13',

l6 and 11 respectively. Shaft 59 is bored axially at 84 and 85 to provide conduits therethrough, and radially at 86 and 81 to connect conduits 84 and 85 with grooves 8 l and 82, respectively. Near.

the opposite end of shaft 59 other radialbores 88 and 89 connect conduits 84 and 85 to passageways 98 and SI, which are traceable to the web side of clutch operating diaphragms 53 and 54.

Thus it will be apparent that when the valves in valve block 14 are so positioned: as to admit fluid under pressure into groove 8|, the fluidpressure will be transmitted through the several interconnected bores to expand diaphragm 53 and thereby operate second speed clutch 39. Similarly, when the valves are so positioned as to admit fluid under pressure to groove 82, the pressure will be transmitted throughjthe bores connected thereto to expand diaphragm 54 and operate high speed, or direct drive clutch 40. Thepressure in passageway 9| is also transmitted to the back of a concentric piston 92, which thereupon moves to the left to expose port 93 communicating with the auxiliary diaphragm 85 to increase the normal pressure on friction surface 34 and insure rotation of drum 2| with fly wheel 24 without slipp e. Said piston 92 is'returned to its right hand position by pressure in bore 84, which is transmitted through a radial bore 94 to the left of piston 92 and maintains pressure behind web when ,the second speed train is operative.

Governor l9 (Figs. 13 and 4) is comprised of a collar 95 splined to shaft 59 to which collar is fixed a housing 95 having anopen side. An axiall movable cam surface 9'! is mounted in the open side and is normally biased to the right (Fig. 113) by the action of a coil spring 98 which is compressed between'a flange on a collar 99: and an iii-turned flange 588 on housing 98. Collar 99 is provided with an eccentric disc it! which cooperates withspaced pivoted arms E92 and its. Saidspaced arms are non-rotatably secured to a shaft i0 3 to the opposite end of which slot connection to the governor valve stem 606. Included between housing 98 and cam surface 91 is a plurality of weights it? which contact housing 98 and surface 8'6 through anti-friction balls J08,

Rotation of the governor housing causes weights it? to fly outward, thereby moving camming surface 97 and its associated collar 99 and is secured an arm 1% connected by a pin and eccentric disc it to the left (Fig. 1B). In its motion to the left, disc Ml encounters arm H38 and rotates it counter-clockwise (Fig. 4), thereby causing valve stem ltd to move to the left. This rotation occurs in two stages corresponding to the second and third speed positions of the governor valve. The degree of movement is determined by stepped camming surfaces int and ms" on arm 503. The return of valve '86 to low speed position is accomplished through arm 802 which is rotated clockwise by eccentric ill! in two stages corresponding to second and low speeds:

. ing collar lilagainst ring 528.

22d and 525 will thereupon engage and tend to suitably secured to some part of the carsuch as the dash or floor-board. The .valve has three positions, high, second and low, with high as the normal position. Pushing button I09. until it contacts housinl H0 establishes the p sition for second speed andcontinuing the mo ion of the button until the button and housing I III are telescoped in housing llLestablishes the position for low speed. Suitable coil springs ll2 and 8 return housing H8 and then buttonv I09 to thelr normal positions.

. The description thus far has been concerned with. the means for obtaining the various speed reductions and the controls by which the reductions are predetermined. It. will be recalled that through a positive two-way clutch. Such a clutch will now be described.

Sleeve 48- is extended to the right (Fig. 1B).

of gear 49 and has formed on its end a series of -ext'emal teeth 4 having chamfered ends H5. The adjacent portion of shaft 59 has external splines H6, and a bell-shaped collar H1 is internally splined to lock non-rotatively Von splines H8, but to permit relative axial movement with respect thereto. The end 8 of collar H1 is accurately machined to fit into valve block 14 and to extend into groove as therein, thus to form an axiall movable piston, Within the belied portion of collar H! are intemal teeth .5 i9 which are likewise chamfered at their ends J28. Teeth H4 and H9 formtwo elements of a Maybach type of positive clutch, the chamfered endsof the teeth rendering engagement of-the teeth difilcult, if notlmpossible, until the speeds of both elements are the same.

To eliminate tooth clash between teeth 5 l4 and l 19, a blocker is used. In the form illustrated,

the blocker comprises a ring 529 having camming surfaces l N formed on spaced internal pro- -;lections M2, said cammlng surfaces 52! cooperating with pins H23 extending radially from sleeve 48.. A friction surface 524 on bell-shaped collar ill/cooperates with an opposed friction surface 925 on ring 820, and a suitable spring E26 urges ring iidto the right (Fig. 113) to engage saidfriction surfaces.

When it is desired to lock the transmissionin second speed. valvell is operated to admit oil under pressure behind piston H8. thereby mov- Friction surfaces rotate ring H8 relative to sleeve 88. 'Such relative rotationwill cause cam surface it! to move along pin i3 3 and thereby to.resist the leftward movement of collar 5 H. resistance will persist until the speed of sleeve 88 becomes greator than that of shaft 59, as for example, when the accelerator is momentarily depressed, whereupon teeth 519 will engage smoothl-y'with teeth ill and the transmission will be locked :n second speed as shown in Fig. 8. The teeth will remain locked as long as there is pressure behind piston H8. 5

Release of this pressure by the operation of valve 11 will permit spring I25 to return collar II1 to its non-engaged position.

It is apparent that for thesuccessful operation of the transmission in accordance with the objects to be attained thereby it is necessary first, I that the manually controlled valve and the second speed lock up valve do not interfere with the normal operation of the governor valve, second, that the manually controlled valve take over. the control of the transmission from the governor valve whenever necessary, and third, that the second speed lock-up valve be operative whenever desired, i. e., whenever the transmission is conditioned for second or high speed. The means by which these conditions are satisfied in the present invention'are shown in detail'in Figs. 9 to 18 inclusive, to which attention is now directed.

The three valves 15, 16 and 11 are shown in Figs. 9 to 18 inclusive with valve block 14 sectioned along line A-.A.of. Fig. IE to show the inter-connection between the valves. Each valve is comprised of a piston I21, I28 and I29, respectively, and a sleeve I30, I 3|, I32, press-fitted into bores in valve block 14. Said block 14 is provided with an intake port I33 (shown only in part) and outlet ports I34, l35 and I35 which communicate with grooves 82, BI and 83, respectively and thence, with the high speed and second speed clutches and piston N8 of the second speed lockup mechanism. The sleeves I30, I3I- and I32 are provided with ports which intercommunicate, as shown, with the portions of pistons I21, I20 and I29 included between lands I31 on the pistons to form passages for the oil. For

ease in tracing the course of the oil through the valves, the paths in each case are indicated with arrows.

In Fig. 9 the valves are shown positioned for normal high gear operation. In this position pump pressure is fedto both the second and In Fig. 10 the transmission is locked up in second with manuallyoperated valve in high speed position. Oil under pressure is fed to the second speed oil clutch and to the second-speed lock piston II9. It will benoted that the high speed oil clutch is bled at the left side of the lock valve as shown. The high speed 011 clutch being thus disengaged and the pump pressure teeth II4, second speed drive will be taken' on second speed free wheel clutch 4'5 and the second speed coast load will be taken against the flat side of teeth II9.

. In coming to particular position-from nor- .mal high gear-operation, the driver has operated lock valve 11 only and may or may nothave opened the throttleat the instant of lock valve operation. High speed clutch '40 will be vented as shownrand should the throttle remain closed,

teeth II 9 will tend to move'into engagement with- Low speed and second speed teeth II4, since shaft 59 always turns faster than sleeve 48 when in thirdor high speed, or when the throttle is closed and the car is tending to free wheel in second. To allow teeth H9 to engage fully, it is necessary for the driverto open the throttle, thereby taking up sec'ond speed drive on the free wheeling clutch 46 and synchronizing shaft 59 and sleeve 48, after which the throttle may be closed to allow the car to coast against the engine. Upon such closure of the throttle, chamfers H5 and I slide relative to one another until the teeth engage and full locking takes place.

To return to high speed, it is necessary that the driver again open the throttle, taking up the drive on the second speed free wheel clutch, and

' then push lock valve 11 to its inoperative positending to force teeth II9 into engagement with tion. If driving torque is maintained on the second speed free wheel clutch, belled sleeve I I 1 will automatically be disengaged by spring I26 and subsequent engagement .of the high speed oil clutch 40 will bring the transmission into normal high gear.

Fig. 11 shows governor valve 16 in high speed position, lock valve 11 in inoperative position and manually operable valve 15 in second speed position, i. e., button I09 is depressed to its first posi-' tion to establish free wheeling second speed. Pump pressure is thus admitted to second speed clutch 39 as shown and the left hand on piston I21 acts as a stop, dead-ending the fluid pressure so that it cannot be admitte'd to high speed clutch 40, or escape and allow the pump pressure to drop. Any fluid previously contained in high speed clutch 40 or the various bores and passageways leading to it is .vented at the left end of valve 15 as shown. Under these conditions the car will free wheel when the throttle is closed,

and the engine will drive the car in second speed through free wheel clutch 45 when the throttle is open.

If desired, the driver may pull out lock button and thereby move lock valve 11 toward the With the valves as shown in Fig. 11, it will be observed that any leakage tending to accumulate behind lock piston I28 is vented to the right of lock valve 11, thereby allowing spring I26 to keep the teeth fully separated and positively preventing contact of the teeth until the driver acts definitely to lock up the transmission in second speed.

Fig. 12 shows the second speed lock valve operated and the manually operated valve in second speed position. In this combination, oil under pressure is forced behind bellows 53 to operate second speed clutch 39 and into groove 83 behind the lock-up piston II9. Oil from high speed clutch 40 and its associated channels escapes at the left end of manually operated valve 15 as shown. With this combination, the throttle manipulation and action of the chamfered portions II 5'and I20 on teeth -II4and II9 will be as de-' scribed in connectionwith Fig-10. I

In Fig. 13, the governor valve 15 is in high speed position, lock valve 11 is inoperative, and manually operated valve 15 is in its low speed position. Oil under pressure thus passes around governor valve 15 in the usual manner, but

escapes at the left end of valve 15 and the oil pressure, therefore, drops substantially to zero. Under such conditions, both second and high speed oil clutches and-49 respectively, are also vented at the left of valve 15. Clutches 39 and right to establish subsequent second speed lock- 2,282,591 40 are free of pressure, since they are entirely cut oil from the pump and drive is taken through speed responsive clutch 30 and the low speed transmission gear train. Low'speed is capable of free wheeling at all times. It might be mentioned that since governor valve 16 is in'high and the car speed must. therefore, be above or 11 miles per hour, this combination will seldom if i ever, exist.

Passing now to Fig. 14, which represents an 10 extension of the valve combination of Fig.- 13, the

lock valve 11 is operated, and valves 15 and '16 remainas in Fig. 13. It is evident that even though a channel is now open to groove '83 behind second speed lock-piston |l8, the escape of 15 wheeling second speed with manually operated valve 15 set for high speed. This combinatiom and those of Figs. 16, 1'7 and 18 show the governor valve 16 in its second speed position, whereas the combinations shown in Figs. 9 to 14 inclusive'show the governor valve I6 in high. I

It will be noted that. inFig. 15 oil under pressure is admitted to second speed clutch 39 only, and that high speed clutch 40 is vented at the left of the governor valve as shown. As in foretend to accumulate behind lock piston i It escapes at the right end of the lock valve and pressure,

' therefore, cannot be built up to overcome sprin 126. With open throttle, drive will be taken through the second speed free wheel clutch 46, while with closed throttle, the car will free wheel.

In Fig. 16, the second speed is locked up and,

manually operated valve l5is in high speed position. This combination follows that of Fig. 15, in that the driver has pulled out button Bill on the instrument panel, thereby moving lock valve ii to its operative position. Pressure is maintained on the second speed clutch 39 and oil under pressure is also admitted behind lock piston H8. High. speed oil clutch to is vented to the left of lock valve ll. If the throttle is closed, teeth m and no will tend contact on "their chamiers Hi5 and lid, but will be prevented from doing so by balk ring 829' continually while the car is free wheeling. However, if the throttle is opened, the engine will drive the car through the second speed free wheel clutch to and teeth lid will move into complete engagement with teeth ii i. After such engagement, the car may be allowed to brake against the engine merely by closing the throttle.

Fig. 17 shows the condition for free wheeling second speed with valve is in second. The path of oil under pressure showing through the valves to the second speed clutched is clearly indicated..

while oil from high speed clutch dd escapes at the left end of manual valve it as in Figs. 11, i2, i3

and 14. It will be noted that any leakage 'tending to accumulate behind lock piston lid is vented 70 at the-right of lock valve ll so that spring itd keeps teeth iii and H9 separated-at all times .with the combination shown in Fig. 37. Said combination may follow that of Fig. 15, in that although such. position has no effect on the oil clutches, since the governor valve I0 is already in second speed position. V

The last figure (Fig. 18) shows the condition for second speed lock-up with the manual control in second speed. Pressure lsmaintained in the channels leading to second speedclutclr 19,

while oills admitted to groove 83 behind lock the left of manual valve II.

Assuming that governor valve is shown in Fig.

18 were in the second speed position and that button III! were released by the driver, thereby allowing valve I! to move to the left, high speed would still be inoperative until the driver had pushed lock valve 11 to its inoperative position and governor valve 16 had also moved into high. Conversely, were manual valve [5 maintainedin 29 the position shown in Fig. 18, and were governor valve 16 moved toward the left, high speed would not become operativeand the combination would 1 then be as shown in Fig. 12.

However, "combinations other than those illustrated may be readily deduced.

It is important to notethat if the car is in second speed lock-up and is allowed to coast to so, a'stop, second speedoclutch 39 will release autono trouble is encountered by the driver in bring- 7 going valve combinations any leakage which may 40 open the throttle without moving lock valve 11 to its inoperative position, belied collar Ill could not move toward ring I28 so long as governor valve 18 remained in low speed position... Upon movement of governor valve iii. to second, however, belied collar ill would be urged forward by oil under pressure. 'ieeth lid and H9 would be prevented from ratcheting. on chalnfers H5 and 520 by ring in until second speed clutch 3d became fully engaged and gear ti and shaft so 59 were rotating at the same speed. Synchronim of shaft 59 and gear dd would allow teeth lid and lid to engage fully, and upon a subsennent closing of the throttle, the car would coast against the engine in second.

as it is understood that the ioregoing description is-merely illustrative of a preferred embodiment of the invention and that the scope oi the invention, therefore, is not to be limited thereto, 7

but is to be determined by the appended claims.

a K claim: I i

in a transmission, driving and driven elemerits, low, second and high speed trains connectable between said elements, fluid-operated means ior rendering said second and high speed .65 trains eflective, overrunning clutches in said low andsecond speed trains, a fluid operated twotvay clutch connected inparallel with the overrut clutch inthe second speed train, a com-- mon source of fluid under pressure, and control means iorsaid fluid adapting said two way clutch to hexoperated when. the second speed fluid-operated clutch is operated, whereby the transmission may be connected for two-way drive in second speed to enable the driven element to drive the" driving element.

ing manual 'valve is to second speed position,

piston 8. High speed clutch 40 is vented at The valve positions shown in Figs. 9 tol8 in-@ I I clusive do not represent all possible positions.

'a piston associated with the movable element,

and means for admitting fluid under pressure behind said piston to operate said clutch.

4. A transmission as described in claim 1, said two-way clutch comprising a jaw 'clutchhaving fixed and movable toothed elements, said teeth being chamfered so that engagement thereof does not occur until there is a relative reversal of torque between the elements.

5. In a transmission, driving and driven shafts, low, second and high speed gear trains, connectable between said shafts, a common source of fluid under pressure, fluid-operated means for rendering said second and high speed'trains effective, overrunning clutches in the low and secand speed trains, a two-way clutch connectable in parallel with the overrunning clutch and fluidoperated means in the second speed train, said two-way clutch comprising axially fixed and movable elements, a piston associated with the movable element, and means for admitting fluid under pressure behind said piston to operate said clutch; and control means for said fluid under pressure, said control means including a manually operable valve for selecting the speed trains operable upon the initial movement of the movable element to prevent the engagement of the clutch except upon a reversal of torque between the fixed and movable elements 8. A transmission as described in claim 5, the elements of the two-way clutch being formed with chamfered teeth to prevent engagement thereof until said teeth are synchronized, a friction surface on the movable element, an axially movable ring surrounding the teeth of the fixed element and having a friction surface adapted to engage the friction surface on the movable element, spring means urging said movable ring toward the movable element to disengage the clutch, and cam means between the fixed element and movable member and adapted upon initial engagement of said friction surfaces, to advance said member to prevent engagement of the teeth of the clutch elements until a relative reversal of torque'occurs between said elements.

PALMER ORR. 

